GnRH neurons, as key elements of the reproductive neuroendocrine system, have important central regulating role in the dynamics of the hormonal cycle. A Hodgkin-Huxley type neural model is proposed in this paper, that...
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GnRH neurons, as key elements of the reproductive neuroendocrine system, have important central regulating role in the dynamics of the hormonal cycle. A Hodgkin-Huxley type neural model is proposed in this paper, that takes into account up-to-date biological literature data related to ion channels. The proposed neuron model is highly nonlinear in parameters and the evaluation of the objective function is computationally expensive, therefore the asynchronous parallel pattern search (APPS) procedure has been used for identification. The model with high number of estimated parameters provides a qualitatively good fit of both voltage clamp and current clamp traces.
The paper presents an iterative uncertainty modeling and robust controller synthesis method for linear parameter-varying (LPV) systems in linear fractional transformation (LFT) form. The goal of the method is to impro...
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The paper presents an iterative uncertainty modeling and robust controller synthesis method for linear parameter-varying (LPV) systems in linear fractional transformation (LFT) form. The goal of the method is to improve robust performance by exploiting modeling freedom in the structured uncertainty descriptions while ensuring model consistency with respect to measurement data. The proposed iterative algorithm consists of three steps: robust LPV controller synthesis, tuning of the uncertainty model and performing closed-loop experiments for new validation data.
This paper extends former results about the networked reference tracking control of a pressurizer in a pressurized water nuclear power plant. An L2-gain based method is used in a deterministic framework to compute the...
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This paper extends former results about the networked reference tracking control of a pressurizer in a pressurized water nuclear power plant. An L2-gain based method is used in a deterministic framework to compute the maximum allowable transmit intervals (MATIs) for the actually implemented dynamic inversion based controller that still guarantee the required performance. Furthermore, a stochastic linear quadratic regulator with a state estimator is also designed that can take packet losses into consideration. It is shown through the comparison that both methods are applicable for networked control but the LQ controller combined with a Kalman filter has better output variance properties.
Eye tracking is widely useful in several fields especially in medical field to help human diagnosis and treatment. The proposed of this study is to develop eye tracking system using intensity measurement algorithm and...
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In this paper, fault detection methods for hydraulic systems based on a parity equation approach with neural net models are presented. Hydraulic systems are used in manifold applications in industry. They are however ...
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In this paper, fault detection methods for hydraulic systems based on a parity equation approach with neural net models are presented. Hydraulic systems are used in manifold applications in industry. They are however not yet the subject of intense research in the area of fault detection and diagnosis, which can be mainly attributed to their strong nonlinear behavior, which exacerbates the physical modeling extensively. To avoid the difficulties associated with the physical modeling, a data-driven modeling approach based on the LOLIMOT neural network will be presented in this paper. Different subsystems of the hydraulic servo axis will be modeled using different sensor configurations. Experimental data from a real testbed allow to compare the model fidelity of the different resulting neural nets and can also be used to illustrate the capabilities of the parity-equation based fault detection approach, which in general allows the detection of tiny faults, such as sensor offset faults in the area of a few percent of the maximum sensor readout.
The paper proposes a measure of robust performance based on frequency domain experimental data that allows nonconservative modeling of uncertainty. Given the nominal model of the plant and closed-loop performance spec...
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In this paper, a model predictive controller is developed for controlling the main primary circuit dynamics of pressurized water nuclear power plants during load-change transients. The hybrid model of the plant is suc...
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As fault detection and fault diagnosis are more and more finding their way into modern industrial mechatronic products, it is now time to take the next step. Based on the research efforts for fault detection and diagn...
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As fault detection and fault diagnosis are more and more finding their way into modern industrial mechatronic products, it is now time to take the next step. Based on the research efforts for fault detection and diagnosis, a platform has been prepared for research on fault management, i.e. automatic reactions of the system to continue operation after the detection of faults. These reactions may employ hardware redundancy (i.e. switching from a faulty actuator to another, intact one) or analytical redundancy (i.e. switching from a faulty sensor to a “model sensor” or “soft sensor”). A total fault tolerance concept must encompass all components of a system, i.e. the actuators and drives, the sensors as well as the controller and communication. In many cases, a degradation of functions has to be accepted after a fault has appeared. This contribution will center on actuators and drives showing real-world examples of prototypical realizations and examples from industrial products. Concentrating on the most widespread actuation principles, the paper will focus on electric drives and hydraulic actuators. First, a review is given on fault tolerance principles and general structural considerations e.g. hot-standby and cold-standby, focusing on the scheme of an overall fault-tolerant control system. Then, fault statistics for real actuators and drives will be presented. These fault statistics give hints on the parts of the actuators that are most susceptible to faults. Different designs of fault tolerant actuators and drives, which have been realized, shall be presented and evaluated with respect to their capabilities of sustaining faults. Finally, an outlook for fault-tolerant mechatronic systems will be given.
This paper is devoted to the construction of wavelet-type transforms with the purpose to represent functions belonging to the Hardy-space H 2 . The concept of the affine wavelet-transform defined in the space L 2 is e...
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This paper is devoted to the construction of wavelet-type transforms with the purpose to represent functions belonging to the Hardy-space H 2 . The concept of the affine wavelet-transform defined in the space L 2 is extended to the Hardy space H 2 on the basis of the Blaschke group. A discrete hyperbolic wavelet scheme is also constructed that results in computable forms. The wavelet construction obtained possesses good localization properties with respect to functions in H 2 , hence forms an adequate tool for signal and system identification purposes.
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